1. Field of the Disclosure
The disclosure relates to a robot finger and a robot hand.
2. Discussion of the Background Art
Robot hands are modeled after the human hand and comprise a hand base substantially corresponding to the palm of the human hand. To said hand base, at least one and, normally, a plurality of robot fingers are fastened. The robot fingers comprise a plurality of finger limbs which are likewise modeled after the human fingers. By way of a base joint, a main finger member is fastened directly to the hand base or to a base member of the robot finger. In this configuration, said base joint is the finger joint arranged closest to the hand base. The base joint is designed to allow movement of said main finger member in two planes. Further, in a manner corresponding to the closing or opening of the hand, the main finger member can also be turned or pivoted about a main pivot axis. Vertically thereto, the main finger member can normally be moved laterally by about 10° to 20° in both directions. Thus, the robot finger can be moved within spatial limits corresponding to those of the moving range of a human finger. It is known to provide the base joint as a joint comprising two pairs of bevel gears. The two main bevel gears of the base joint are arranged opposite to each other and can be driven independently of each other. Rotation of the main bevel gears about the main rotational axis will cause a turning or pivoting of the fingers corresponding to the opening or closing of the hand. Between the two main bevel gears and vertically to them, two intermediate bevel gears are arranged. By rotating the main bevel gears with different rotational speeds and/or in opposite directions, there is effected a lateral pivoting movement of the robot finger and the main finger joint of the robot finger. The two main bevel gears are driven by a respective electric motor via a transmission such as e.g. a toothed belt. Said electric motors are preferably arranged on the base member of the robot finger or integrated therein.
When a gripping action is performed by a robot hand, counterforces opposed to the holding forces will occur particularly at the fingertips. These counterforces have to be transmitted via the base joint to the base member of the robot finger and/or to the hand base of the robot hand. Due to the provision of bevel gears, the influence of such forces onto the intermediate bevel gears has the consequence that the base joint will be pressed apart. As a result, the abutment faces between the teeth of the bevel gears that are effective for force transmission will become smaller, which in turn may entail damage to the bevel gears. In this regard, it may even happen that a tooth will be skipped or the base joint will become jammed. Further, irrespective of the force transmission problem, there is a danger of foreign bodies intruding into the bevel gear, thus causing the bevel gears to jam or to become damaged.
It is an object of the disclosure to provide a robot finger wherein the danger of damage to the base joint due to the occurring forces and/or due to contamination is avoided.